Writing information on substrate displays

ABSTRACT

The present disclosure describes writing information on substrate displays. In an example, a display on a substrate is interfaced. The interfacing includes constraining a first longitudinal side of the substrate via a first actuable slot. Further, a second longitudinal side of the substrate opposite to the first longitudinal side is constrained via a second actuable slot. Thereby the substrate is constrained between the first and second slot with the display positioned therebetween. Further, the display is operated to write information thereon via an imager while the substrate is constrained between the first and second slot.

CROSS-REFERENCE

This application is a Continuation of U.S. patent application Ser. No.15/036,793, filed May 13, 2016, entitled “WRITING INFORMATION ONSUBSTRATE DISPLAYS”, which claims benefit to PCT/US2013/077570, filedDec. 23, 2013, entitled “WRITING INFORMATION ON SUBSTRATE DISPLAYS”,both of which are incorporated herein by reference.

BACKGROUND

There are a variety of applications in which it is advantageous tointeract with a user via a substrate including an information display.Examples of such substrates include handheld cards or labels including adisplay region to show information for a user. Such a handheld card maybe used for a variety of applications including security access cards orgift cards.

The information display may be a rewritable display in which informationmight be dynamically rewritten. For example, when entering a facility, awriting device may write text and/or images onto an electronic imagingsubstrate strip of a security card. The text may indicate the time anddate of entry while the images may include various logos that change bythe day and that security personnel will recognize. In another example,a gift card may have an initial balance displayed onto an electronicimaging substrate strip. When a customer uses the gift card, the newbalance can be rewritten by a writing device used by the retailer.Additionally, various logos or advertisements may be rewritten onto theelectronic imaging substrate strips of the cards as customers use thecard.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the present disclosure may be well understood, variousexamples will now be described with reference to the following drawings.

FIG. 1A is a schematic illustration of a substrate including a display.

FIG. 1B is a schematic top view of the substrate of FIG. 1A constrainedby a constraining arrangement.

FIG. 1C is a schematic front view of the substrate of FIG. 1Aconstrained by a FIG. 1D is a schematic front view of the substrate ofFIG. 1A constrained by a constraining arrangement in a closed position.

FIG. 2 is a schematic cross-section of a substrate during operation of awriting system according to examples herein.

FIG. 3A is a schematic perspective of a system to write information on asubstrate FIGS. 3B and 3C are schematic cross sectional views of thesystem of FIG. 3A in, respectively, an open and a closed position.

FIGS. 4A and 4B illustrate example mechanisms to implement constrainingelements according to some examples.

FIGS. 5A and 5B are schematic perspectives of a system to writeinformation on a card according to examples.

FIG. 6 is a flow chart for implementing at least some of the examplesdisclosed herein.

FIGS. 7A and 7B are schematic side views of an mechanism to implementconstraining elements in examples herein.

FIGS. 8A to 8C schematically show a further system to write informationon a card according to examples herein.

DETAILED DESCRIPTION

In the following description, numerous details are set forth to providean understanding of the examples disclosed herein. However, it will beunderstood that the examples may be practiced without these details.While a limited number of examples have been disclosed, it should beunderstood that there are numerous modifications and variationstherefrom. Similar or equal elements in the Figures may be indicatedusing the same numeral.

As mentioned above, a substrate may include a re-writable display thatcan be used to display information to a user. In the rewritable display,information might be dynamically written. For the dynamic writing, awriting system can be used. However, it might be challenging to providesystems that can adequately write information on the substrate whileproviding a satisfactory user experience during the writing experience.

In light of this, and other factors, the present disclosure describes awriting device with a substrate constraining arrangement configured tosuitably constrain the substrate during writing while allowing a user toexternally monitor the information being written on the substratedisplay.

FIG. 1A shows a substrate 100 including a variable display 102. FIG. 1Aillustrates substrate 100 as a gift card in which a remaining amount ofcredit and marketing information 106 are displayed in display 102. Asillustrated in FIG. 1A, substrate 100 includes a first longitudinal side108 and a second longitudinal side 110 opposite to first longitudinalside 108. Display 102 is provided between first and second longitudinalsides 108, 110.

Display 102 may correspond to any display type suitable to dynamicallymodify information shown thereon. For example, display 102 maycorrespond to a quasi-permanent display such as electronic paper(e-paper). E-paper may be composed of a set of sandwiched layers. Onelayer may include an array of embedded, spherically-shapedmicrocapsules. Another layer may be a conductive ground layer contiguousto the micro-capsule layer. A further layer composed of a transparentconductive material may be provided contiguous to the micro-capsulelayer. The microcapsules can be filled with one or more pigmentparticles that can be used to display images by looking at the e-paperfrom the insulating layer side. The conductive layer may serve as groundlayer for externally writing on the e-paper using an ion source asfurther described below with respect to FIG. 2. Substrate 100 includes abody 114 made of plastic or any other suitable material. Body 114 may beflexible to prevent damages on substrate 100 caused by excessive bendingor other unintended strain exerted thereon. Electronic paper as displayelement facilitates a flexible implementation of substrate 100. Aflexible substrate is convenient for implementing robust cards that maybe carried on a pocket, wallet or similar. Moreover a certainflexibility of substrate 100 facilitates a planar constraining thereofthat facilitates externally writing on display 102 as further describedbelow. Display 102 may be provided with an e-paper configuration thatomits a circuitry underneath for writing information thereon. In otherwords, display 102 may be provided with passive electronic paper thatomits an electrode array for addressing single pixels and other activeelements such as a processor for operating the electrode array or anenergy source for energizing the electrodes and the processor. Thewriting process may be performed using a charge source as furtherdetailed below with respect to FIG. 2. More specific examples on howsuch an e-paper structure may be constituted are further detailed in USpatent application with publication number US20110298760, which isincorporated herein by reference in its entirety (to the extent in whichthis document is not inconsistent with the present disclosure) and inparticular those parts thereof describing e-paper configurations. Asused herein, a longitudinal side of substrate 100 refers to a substrateside in the direction of a length of the substrate. In the illustratedexample, substrate 100 is rectangular and first and second longitudinalsides correspond to a longest length 112 of the substrate. It will beunderstood that a longitudinal side must not correspond to a longestlength of a substrate.

FIG. 1B shows a side view of a portion of a system 116 to writeinformation on display 102 of substrate 100. System 116 includes aconstraining arrangement 118 to constrain substrate 100 so thatinformation can be written on display 102 as further set forth below.Constraining arrangement is shown with a first constraining element 118a to constrain substrate 100 at first longitudinal side 108 and a secondconstraining element 118 b to constrain substrate 100 at secondlongitudinal side 110. As illustrated below with respect to FIGS. 1C and1D, constraining elements 118 a, 118 b include actuable slots forreceiving sides 108, 110 of substrate 100 and effect the constraining byreduction of the slot width.

In the example of FIG. 1B, constraining arrangement 118 is designed toreceive substrate 100 in a landscape position. In other words,constraining elements 118 a, 118 b correspond to the longestlongitudinal sides of substrate 100, i.e., first and second longitudinalsides 108, 110. In other examples, a constraining arrangement can bedesigned to receive substrate 100 in a portrait position. In otherwords, constraining elements 118 a, 118 b may correspond to the shortlongitudinal sides of substrate 100, i.e., longitudinal sides 128, 130.

FIG. 10 shows a front view of the portion of writing system 116 shown inFIG. 1B. As shown in FIG. 10, a first slot 120 a is formed at a gap offirst constraining element 118 b formed between two opposing slotmembers 120 a.sub.1, 120 a.sub.2. A second slot 120 b is formed at a gapof second constraining element 118 b between two opposing slot members120 b.sub.1, 120 b.sub.2. Slots 120 a, 120 b are actuable for effectingthe constraining of substrate 100. An open position of slots 120 a, 120b is shown in FIG. 1C, a closed position of slots 120 a, 120 b is shownin FIG. 1D. Slots 120 a, 120 b are to receive respective longitudinalsides 108, 110 of substrate 100. Therefore, constraining arrangement 118is dimensioned according to the dimensions of the specific type ofsubstrate to be processed by writing system 116. For at least someapplications, substrate 100 may be flexible and be bent when no pressureis exerted thereon. A bent substrate 100 is shown in FIG. 10, thesubstrate curvature being exaggerated for the sake of illustration. Forexternally writing on display 102 it might be advantageous thatsubstrate 100 is held flat, since a certain curvature of display 102 maycompromise quality of information written thereon. According to someexamples herein, actuable slots 120 a, 120 b that receive longitudinalsides of the substrate provide a required flatness to substrate 100thereby facilitating writing on display 102 and visual access theretoduring the writing process. A user can then externally monitor theinformation being written on the substrate display.

Slots 120 a, 120 b are actuable so as to respectively constrain firstand the second longitudinal substrate sides 108, 110. In the illustratedexample of FIG. 1, the constrainment is implemented by effecting areduced slot width. However, it will be understood that any suitableconstrainment approach may be applied. For example, constraining forcesmay be applied at the slot via electrostatic actuation or by other meanssuch as by a vacuum constrainment.

As used herein, a slot width refers to the extent from slot member toslot member. Slot width is indicated in FIG. 10 by the up down arrowsbetween, respectively, slot members 120 a.sub.1-120 a.sub.2 and slotmembers 120 b.sub.1-120 b.sub.2.

In the illustrated example, slots 120 a, 120 b can be actuated in adownward direction 128 to constrain substrate 100 as shown in FIG. 1D.It will be understood that there are a variety of options forconstraining substrate 100. Slots 120 a, 120 b can be actuated in anysuitable direction that facilitates reducing the slot width. In at leastsome examples herein, slots 120 a, 120 b are operatively coupled to anactuation mechanism (not shown) that imparts the constraining force tothe slots. The actuation mechanism includes suitable elements to effectthe constraining by imparting movement to the slot elements. Forexample, such an actuation mechanism may include a combination ofmechanical linkages and clamps that actuate the slot elements andenables generation of the constraining forces. Such an actuationmechanism may be automatically or manually actuated to engender thenecessary torques for the constraining. Some examples of actuationmechanisms are illustrated below with respect to FIGS. 4A, 4B.

FIG. 1D shows a front view of the portion of writing system 116 shown inFIG. 1B with slots 120 a, 120 b in a closed position. As illustrated byFIG. 10, slots 120 a, 120 b in the closed position facilitate thatsubstrate 100, and consequently display 102, lies flat. A transparentvolume 122 is formed between first and second slot 120 a, 120 b so thatdisplay 102 is externally viewable by a user 124 while first and thesecond longitudinal substrate sides 108 are constrained at first andsecond slot 120 a, 120 b. Transparent volume 122 may be an empty spaceor include a transparent element such as glass, transparent plastic orthe like extending between constraining elements 118 a, 118 b.

As shown in FIG. 1D, system 116 includes an imager 126 to operatedisplay 102 in an area opposite to transparent volume 122 while firstand second longitudinal substrate sides 108, 110 are constrained byfirst and second slots 120 a, 120 b. Imager 126 may write on display 102by projecting charges 132 on display 102 so as to change pixel states.As can be noticed from FIG. 1D, system 116 provides the requiredflatness to substrate 100 without hindering writing on display 102.Moreover, a user 124 has real-time visual access the information beingwritten on the substrate display 102.

In the example of FIGS. 1A to 1D, the slots for card constraining arecontinuous. In other words, slot members 120 a.sub.1, 120 a.sub.2, 120b.sub.1, 120 b.sub.2 are continuous edges to contact respectivelongitudinal sides 108, 110 when slots 120 a, 120 b are closed. In otherexamples, the slots may be discontinuous so that the slot memberscontact multiple segments of the longitudinal sides when the slots areclosed. Generally, the slot members are dimensioned and positioned tocontact a sufficiently high area of the substrate.

System 116 may be designed such that the portion of the media to beconstrained results in a sufficient increase in substrate stiffnesseffected by the slot reduction. A ratio of the stiffnesses between aconstrained case (e.g., the state of substrate 100 shown in FIG. 1D) tothe unconstrained case (e.g., the state of substrate 100 shown in FIG.10) can be used to estimate the relationship of width of the substratecovered by the slots and how much an initial deflection of the substrateaway from a flat shape can be reduced. As used herein, the stiffness ofthe substrate refers to the measured of the resistance it offers todeformation. The stiffness may be mathematically defined as k=F/.delta.,where F is the force applied to the substrate, and .delta. is thedisplacement produced by the force along the same degree of freedom.This mathematical definition can be used to compute the ratio referredto above.

For example, the slots may be to receive between 10 and 45% of a frontsurface of the substrate. An edge coverage of one of the slots may havea width of at least 2 mm. As illustration, if the substrate is sized asa credit card, the substrate may have a bent shape in an unconstrainedstate. The bent shape may have a bow of about 1 mm. In order to decreasethat to about 50 .mu.m, where it would not interfere greatly with atleast some of the writing systems illustrated herein, then a 20.times.reduction of the bow might be required. This might imply a roughly20.times. increase in the stiffness of the substrate. This may beachieved by sizing the slot members to cover 40% of the surface of thesubstrate. Thereby, 60% of the surface of the substrate would still befree for providing the surface onto which information can be written andmonitored by an external user.

FIG. 2 shows a cross-section of a substrate 200 during operation of awriting system 216 to write information on an electronic paper display201. The cross-section is along the electronic display, for example asillustrated by line AA in FIG. 1B.

The cross-sectional view shows an illustrative multilayer structure ofsubstrate 200, including an electronic paper layer 201 withmicrocapsules 207 sandwiched between a charge receiving surface 208 anda conductive ground layer 212. Microcapsules 207 are held within amatrix 214. It will be understood that the electronic paper illustratedin FIG. 2 is merely an example and that other types of electronic papermight be implemented in examples herein.

Writing system 216 is illustrated including a writing module 202, awriting unit 204, and an erasing unit 206. Writing unit 204 and erasingunit 206 are connected to the same side of writing module 202 that faceschargeable surface 208. During the writing process, substrate 200 isconstrained by slots 120 a, 120 b (only slot members 120 b.sub.1, and120 b.sub.2 are depicted in FIG. 2) with writing unit 204 suspendedabove surface 208. Further, a user 124 has access to an image beingwritten on electronic display 201 via the transparent volume formedbetween slots 120 a, 120 b (e.g. transparent volume 122 shown in FIG.1D).

In the example of FIG. 2, writing unit 204 is an ion head. Erasing unit206 can be an electrode that comes into close contact with, or can bedragged along, surface 208 in front of ion head 204. Writing module 202can be moved in the direction indicated by the arrow and e-paper display201 can be held stationary. Alternatively, the e-paper display 201 canbe moved in the opposite direction and writing module 202 heldstationary. Alternatively, writing module 202 and e-paper display 201can be moved simultaneously. In the example shown in FIG. 2, the blackparticles and the white particles of the microcapsules are positivelycharged and negatively charged, respectively. Erasing unit 206 erasesany information stored in the microcapsules prior to writing informationwith ion head 204. In the example shown in FIG. 2, as e-paper display201 passes under writing module 202, positively charged erasing unit 206can remove negatively charged ions that are attached to surface 208.Positively charge erasing unit 206 also creates electrostatic forces(illustrated by positive charges 220) that drive positively chargedblack particles away from chargeable surface 208 and attract negativelycharged white particles toward chargeable surface 208. By passingerasing unit 206 over chargeable surface 208, information written toe-paper display 201 is erased by positioning the negatively chargedwhite particles near the top of the microcapsules and pushing thepositively charged black particles to the bottom of the microcapsules.

FIG. 2 also shows an illustrative writing operation performed by ionhead 204. Ion head 204 is designed and operated to selectively ejectelectrons 218, shown as black bars, toward chargeable surface 208, whena region of the e-paper display 201 located beneath ion head 204 is tobe changed from white to black. It will be understood that any othersuitable charge source, e.g. a positive ion source, might be used in thewriting unit. As electrons 218 reach surface 208, the negatively chargedwhite particles are repelled and driven away from charge receivingsurface 108, while the positively charged black particles are attractedto negatively charged electrons/ions 218 and driven toward chargeablesurface 218. For example, as ion head 204 passes over microcapsule 207while ejecting electrons, the negatively charged white particles arerepelled away from chargeable surface 218 and the positively chargedblack particles are driven toward chargeable surface 208. The e-paperwriting system 216 is not limited to implementations in which ion head204 discharges electrons and erasing unit 206 erases information withpositive charges. Microcapsules 207 in the e-paper layer can be composedof negatively charged black particles and positively charged whiteparticles. In other embodiments, the ion head 204 can be designed toproduce positively charged ions, which are absorbed by surface 208.Erasing unit 206 can use negative charges to erase information stored inthe microcapsule layer of the e-paper display 201. In other examples,writing unit 204 can be any charge injection device with sufficientaddressability and resolution. For example, writing unit 204 can be aplasma generating needle. Some other examples of write systems areillustrated in granted U.S. Pat. No. 6,982,742 and U.S. patentapplication with publication number 20110298760, which are incorporatedherein by reference in its entirety (to the extent in which thisdocument is not inconsistent with the present disclosure) and inparticular those parts thereof describing e-paper and writing systemsconfigurations. In at least some of the examples herein, theconstraining slots are provided in a moveable tray. In an open positionof the tray the substrate can be inserted in or extracted from the firstand second slots. In a closed position of the tray, the card can beoperated by the imager. An example of such a configuration isillustrated in the following with respect to FIGS. 3A to 3C.

FIG. 3A is a schematic perspective of a system 300 to write informationon a substrate 302. In this specific system substrate 302 is a card.Card 302 includes a first longitudinal side 304 and a secondlongitudinal side 306 opposite to first longitudinal side 304. Card 302further includes a display 308 including electronic paper to displayinformation thereon. Display 308 may be constituted analogously asdescribed above with respect to FIG. 2.

Write system 300 includes a bottom support 310 to support a main body312 of the write system on a flat surface (not shown). Main body 312includes the mechanisms to perform the writing on card 302 such as, forexample, a charge source (shown in FIG. 2 below) to produce a chargebeam to write on the electronic paper as illustrated above with respectto FIG. 2.

A moveable tray 314 is hinged to an edge 316 of main body 312 so that itcan move from an open position (illustrated below with respect to FIG.3B) to a closed position ((illustrated below with respect to FIG. 3C).It will be understood that other types of moveable trays may beimplemented. For example, a slide tray may be implemented. Such a slidetray may be slidable into main body 312.

Tray 314 includes a transparent front plate 318 that facilitates thatdisplay 308 can be viewed by a user once card 302 is inserted into tray314 and, more specifically, while information is being written ondisplay 308. Transparent front plate 318 may be made of a suitabletransparent material such as a transparent plastic (e.g. polycarbonate)or glass. Alternative implementations of the front plate are foreseen.For example, the front plate may have an opaque frame surrounding atransparent window. Display 308 may be viewable through the transparentwindow once card 302 is inserted.

Tray 314 includes a constraining arrangement with a first constrainingelement 320 a for receiving first substrate longitudinal side 304 and asecond constraining element 320 b for receiving second substratelongitudinal side 306. Constraining elements 320 a, 320 b may beconstituted analogously as constraining elements 320 a, 320 b describedabove with respect to FIGS. 1A to 10. An example of an arrangement ofconstraining elements 320 a, 320 b is set forth below with respect toFIGS. 4A and 4B.

FIG. 3B is a cross sectional view of a portion of write system 300 alongline BB, shown in FIG. 3A. FIG. 3B shows write system 300 with tray 314in an open position and card 302 fully inserted. As depicted in theFigure, main body 312 includes an open volume beneath tray 314 throughwhich a charge source 322 can access display 308 to write informationthereon. In the illustrated example, charge source is an addressablecorona source. Charge source 322 may be constituted analogously as thewriting unit illustrated with respect to FIG. 2 above. An erasing unitmay also be combined with charge source 322 analogously as illustratedabove with respect to FIG. 2.

FIG. 3C is a cross sectional view of the portion of write system 300shown in FIG. 3B with tray 314 in a closed position. At the shownposition, charge source 322 has access to display 308. At the closedposition, slots in the constraining elements are actuated to reduce theslot width so as to constrain first and second longitudinal substratesides 304, 306 of card 302. Thereby, constraining elements 320 a, 320 bfacilitate planarity of card 302 at that position so that informationcan be written into display 308 with a satisfactory clarity. An exampleof slots for constraining elements 320 a, 320 b are illustrated belowwith respect to FIGS. 4A and 4B. Moreover, since the slots atconstraining elements 320 a, 320 b are to receive first and secondlongitudinal sides 304, 306 a middle portion of card 302 includingdisplay 308 is viewable for an external user 124 via transparent frontplate 318 while information is being written on display 308. Thereby,user experience can be enhanced. It will be understood that write system300 is described merely as an example and that variations thereof areforeseen. For example, but not limited to, any suitable supportarrangement may be used to support main body 312 not limited to bottomsupport 310. Further, main body 312 may be supported at a verticalsurface (e.g., a wall) using suitable fixations. Further, write system300 may include elements to ensure that tray 314 can be closed only whencard 302 is fully inserted. Tray 314 may be either manually operated toa locked position or automatically brought down via a motorizedmechanism. Such a motorized mechanism might perform tray closing once auser pushes the tray inward. Such a motorized mechanism may initiallyoperate with a small controlled torque to prevent any pinching risk.Once the tray is fully latched, the motorized mechanism may a largertorque to actuate the constraining slots with proper preload, so thatthe substrate is sufficiently constrained.

FIGS. 4A and 4B illustrate an example mechanism to implementconstraining elements 320 a, 320 b. More specifically, these Figuresshow the free end of tray 314 and a portion of write system main body312, with which constraining element 320 b co-operates to actuate slot324. For the sake of simplicity, the Figures only illustrateconstraining element 320 b. It will be understood that constrainingelement 320 a can be implemented analogously.

Constraining element 320 b includes a slot 324 spanning between twoslots members 326 a, 326 b. The lower slot member 326 b is moveablealong a pin 328 so that slot 324 a is actuable to vary the slot width.Lower slot member 326 b is spring loaded against a lock nut 330 using asuitable resilient member 332 (e.g., a spring). Body 312 includes atrench 334 dimensioned and positioned to receive lock nut 330 and aportion of pin 328.

When tray 314 is in an open position (as shown in FIG. 4A) slot members326 a, 326 b are separated and the slot width is at its maximum so thatlongitudinal side 304 of card 302 can be easily inserted into slot 324.When tray 314 is closed (as shown in FIG. 4B), constraining members 326b encounters a top surface 336 of body 312 that produces a displacementof lower constraining member 326 b along pin 328 and towards upperconstraining member 326 a. Thereby, when tray 314 is closed, the slotwidth is reduced so as to constrain longitudinal side 304 betweenconstraining members 326 a, 326 b. In addition to the effectedconstraining of card 302, a high flatness of card 302 is facilitated inthe otherwise bent card. As set forth above, high flatness of card 302facilitates that information can be written on the card display by anexternal charge source. Write system 300 may also include a releseablylatching system so that tray 318 remains at the closed position and canbe opened when required.

In at least some of the examples herein, the constraining slots areprovided in a transparent writing device configured for sidewayinsertion of the substrate. Such a writing device may include asubstrate path via which the substrate is conveyed from (i) an insertionposition where the substrate can be inserted in the system, (ii) furtherto a central position in which the substrate is constrained via a firstand a second slot and the display is operated via an imager, and (iii)to an extraction position from which the substrate can be extracted fromthe writing system. An example of such a configuration is illustrated inthe following with respect to FIGS. 5A and 5B.

FIG. 5A is a schematic perspective of a system 500 to write informationon a card 502. Card 502 includes a first longitudinal side 504 and asecond longitudinal side 506 opposite to first longitudinal side 504.Card 502 further includes a display 508 including electronic paper todisplay information thereon. Display 508 may be constituted analogouslyas described above with respect to FIG. 2.

Write system 500 includes a bottom support 510 to support a main body512 of the write system on a flat surface 511. Main body 512 includesthe mechanisms to perform the writing information on card 502 such as,for example, an erasing unit 514 and a charge source 516. Erasing unit514 may be constituted analogously as erasing unit 206 illustrated abovewith respect to FIG. 2, but adapted to erase information on display 508while card 502 slides beneath erasing unit 514. Writing unit 516 may beconstituted analogously as writing unit 206 illustrated above withrespect to FIG. 2, but adapted to write information on display 508 whilecard 502 slides beneath erasing unit 514.

Write system 500 includes a substrate path 518 via which substrate 512is conveyed for writing information on display 508. Substrate path 518includes a transparent cover 520 placed so that a user can see display508 while being conveyed and, more specifically, while information isbeing written on display 508. Substrate path 518 includes conveyingelements to slide the card therethrough and, more specifically, from aninsertion position 522 to a central position 524 and further to anextraction position 526. In the illustrated example, motorized rollers528 are provided along substrate path 518 to convey card 502therethrough.

First and second constraining elements 118 a, 118 b are provided atcentral position 525 so that card 502 is constrained while erasing unit514 and writing unit 516 are operated. Examples of constraining elements118 a, 118 b are illustrated above with respect to FIGS. 1A to 1D.Constraining elements 118 a, 118 b may constrain card 502 with aconstraining force sufficiently high to achieve a required flatness forwriting, but sufficiently low for allowing that card 502 can slidethrough central position 524.

During operation of write system 500, card 502 is inserted at insertionposition 522. Then, card 502 is conveyed by rollers 528 to centralposition 524. At central position 524, information is written on card502 while sliding beneath erasing unit 514 and writing unit 516.Finally, card 502 is further conveyed to extraction position 526 fromwhich substrate 502 can be extracted from system 512.

FIGS. 7A and 7B illustrate in a side view an example mechanism toimplement constraining elements in for example, a system configurationas shown in FIGS. 5A and 5B. In the example of FIG. 7A, a card 702 witha re-writable display 704 for being processed by a writing system 700.In the illustrated example, card 702 is conveyed to the writing area,i.e. an area at which display 704 can be accessed by an imager 126. Aconveyor belt 706 is provided at a bottom part of system 700 to carrycard 702 to the writing position. Writing system 700 further includes anupper cover 708 with an opening 710 via which a user can visualizedisplay 704 while it is being written via imager 126.

As illustrated by FIG. 7B, card 700 can be constrained at the writingarea by an upper displacement of actuating elements 712 that supportconveyor belt 706. Actuating elements 712 collaborate with contact pads714 (e.g. Teflon pads) to effect a tight constraining of card 700.

FIGS. 8A to 8C schematically show a further system 800 to writeinformation on a display 804 of a card 802. System 800 includes ashuttle 806 for constraining card 802 during writing thereof at anU-shaped slot 808. Card 802 is to be inserted in shuttle 806 and, morespecifically, at slot 808 as shown in FIGS. 8B and 8C. Card insertionmay be implemented via translation of card 802, via translation ofshuttle 806 or a combination of both. For example, shuttle 806 may bestationary and card 802 may be manually or automatically insertablethereon. In another example, card 802 may be held stationary whileshuttle 802 is translated via a suitable mechanism (e.g. using motorizedbelt, lead screws, guide rails or the like).

Slot 808 is adapted to constrain card 802, and more specifically itslongitudinal sides, via an actuation mechanism. In the illustratedexample, as shown at FIG. 8B, the actuation mechanism at the slot is aspring loaded lock 810. Spring loaded lock 810 is comprised of a pin 812attached to a spring 814 for resiliently constraining card 802 in slot808. In this example, card 802 includes a notch 816 to releseablyreceive pin 814.

FIG. 8C shows a more specific configuration of system 800. In the shownconfiguration, card 802 is inserted in shuttle 806 via translation ofshuttle 806 on linear guides 820. Once card 802 is inserted in shuttle806, an imager 822 can access from the bottom (considering the shownperspective) display 804. At the same time, since card 802 isconstrained at its longitudinal sides via slot 808, display 804 isvisible for external inspection while imager 822 writes informationthereon. FIG. 6 shows a flow chart 600 for implementing at least some ofthe examples disclosed herein. In discussing FIG. 6, reference is madeto FIGS. 1 to 5B to provide contextual examples. Implementation,however, is not limited to those examples. At block 602, a firstlongitudinal side of a substrate is constrained via a first actuableslot. For example, looking at FIGS. 1A to 1D, longitudinal side 108 ofsubstrate 100 may be constrained by reducing the size of slot 120 a,i.e. by reducing the distance between slot members 120 a.sub.1 and 120a.sub.2. The constraining may be performed by any suitable actuationsuch as reduction of slot width as illustrated in previous examples, orother means such as electrostatic actuation or by applying a vacuum atthe slot so as to effect a suction force.

At block 604, a second longitudinal side of the substrate is constrainedvia a second actuable slot. The second longitudinal side is opposite tothe first longitudinal side. For example, looking at FIGS. 1A to 1D,longitudinal side 110 of substrate 100 may be constrained by reducingthe size of slot 120 b, i.e. by reducing the distance between slotmembers 120 b.sub.1 and 120 b.sub.2.

At blocks 602, 604, the substrate is constrained between the first andsecond slot with a display positioned therebetween. For example, lookingat FIG. 1D, display 102 is between the first and second slots 120 a, 120b so that it can be accessed by an imager 126 and externally monitoredby an external user 124.

At block 606, the display is operated via an imager while the substrateis constrained between the first and second slot. For example, lookingat FIG. 2, writing module 216 writes on electronic paper 201 whilesubstrate 200 is being constrained via closed slots 120 a and 120 b(only slot members 120 b.sub.1 and 120 b.sub.2 are shown in FIG. 2).Further, since electronic paper 201 is between slots 120 a and 120 b, auser 124 can monitor information being written during the writingprocess, thereby significantly enhancing the user experience.

At block 606, a transparent window may be provided opposite the imagerso that the display is externally viewable during the dynamic operationof the display. For example, looking at FIG. 1D, transparent volume 122allows user 124 to monitor display 102 during the writing information.Looking at FIG. 3C, a transparent plate 318 allows that user 124 tomonitor display 308 during the writing operation. Looking at FIGS. 5A,5B transparent cover 520 is placed so that a user can see display 508while being conveyed through substrate path 518 and, more specifically,while information is being written on display 508.

In at least some of the example above, the substrate is a pocket-sizedcard. The display includes passive electronic paper that is operable bythe imager. The imager is an external element from the substrate. Such asubstrate with a passive electronic paper omits electrodes, processor,or energy sources for individually addressing pixels in the electronicpaper. The pixel addressing is performed by the external imager, e.g., acharge source as illustrated above with respect to FIG. 2.

In the foregoing description, numerous details are set forth to providean understanding of the examples disclosed herein. However, it will beunderstood that the examples may be practiced without these details.While a limited number of examples have been disclosed, numerousmodifications and variations therefrom are contemplated. It is intendedthat the appended claims cover such modifications and variations.Further, flow charts herein illustrate specific block orders; however,it will be understood that the order of execution may differ from thatwhich is depicted. For example, the order of execution of two or moreblocks may be scrambled relative to the order shown. Also, two or moreblocks shown in succession may be executed concurrently or with partialconcurrence. Further, claims reciting “a” or “an” with respect to aparticular element contemplate incorporation of one or more suchelements, neither requiring nor excluding two or more such elements.Further, at least the terms “include” and “comprise” are used asopen-ended transitions.

1. A device comprising: a first constraining element to selectivelyconstrain a first longitudinal side of a substrate; a secondconstraining element to selectively constrain an opposite secondlongitudinal side of the substrate; and a conveying element to engage afirst face of the substrate to cause movement of the substrate, relativeto and via the respective first and second constraining elements, into aposition to write information on a display of the substrate.
 2. Thedevice of claim 1, wherein the conveying element comprises a first beltportion to releasably engage the first face of the substrate to causemovement of the substrate.
 3. The device of claim 2, wherein the firstconstraining element comprises a first slot including opposite, spacedapart first slot members actuable into contact against opposite faces ofthe substrate to constrain the first longitudinal side of the substrate,and wherein a respective one of the first slot members supports thefirst belt portion, and wherein upon actuation of the first slot, thefirst belt portion is to engage the first face of the substrate to movethe substrate.
 4. The device of claim 3, wherein the conveying elementcomprises a second belt portion to releasably engage the first face ofthe substrate to cause movement of the substrate.
 5. The device of claim4, wherein the second constraining element comprises a second slotincluding opposite, spaced apart second slot members actuable intocontact against opposite faces of the substrate to constrain the secondlongitudinal side of the substrate, and wherein a respective one of thesecond slot members supports the second belt portion, and wherein uponactuation of the second slot, the second belt portion is to engage thefirst face of the substrate to move the substrate.
 6. The device ofclaim 1, wherein conveying element is separate from, and independent of,the first and second constraining elements.
 7. The device of claim 6,wherein the conveying element comprises at least one motorized roller torollingly engage the first face of the substrate.
 8. The device of claim7, wherein the at least one motorized roller is located between thefirst constraining element and the second constraining element.
 9. Thedevice of claim 1, comprising: a transparent volume defined between thefirst and the second constraining element to arrange the display to beexternally viewable on a second face of the substrate through thetransparent volume by a user while the first and the second longitudinalsides of the substrate are constrained via the respective first andsecond constraining elements.
 10. The device of claim 9, comprising: animager positioned, in an area adjacent the first face of the substrate,opposite to the transparent volume to operate the display, includingwriting information, while the first and the second longitudinal sidesare constrained by the respective first and second constrainingelements.
 11. The device of claim 10, wherein the display includeselectronic paper and the imager includes a writing device to operate theelectronic paper, including writing information, passing in relation tothe writing device.
 12. The device of claim 10, further comprising asubstrate path via which the substrate is conveyed via the conveyingelement: from an insertion position in which the substrate is insertablein the device; further to a central position in which the substrate isconstrained via the first and the second constraining elements and thedisplay is operable via an imager; and to an extraction position fromwhich the substrate is extractable from the device.
 13. A devicecomprising: a first constraining element to selectively constrain afirst longitudinal side of a substrate; a second constraining element toselectively constrain an opposite second longitudinal side of thesubstrate; and a conveying element to engage at least one face of thesubstrate to cause movement of the substrate, relative to and via therespective first and second constraining elements, into a position towrite information on a display of the substrate, wherein the conveyingelement is separate from, and independent of, the first and secondconstraining elements and the conveying element comprises at least onemotorized roller releasably engageable relative to the at least one faceof the substrate.
 14. The device of claim 13, wherein the firstconstraining element comprises a first slot including opposite, spacedapart first slot members actuable into contact against opposite faces ofthe substrate to constrain the first longitudinal side, and wherein thesecond constraining element comprises a second slot including opposite,spaced apart second slot members actuable into contact against oppositefaces of the substrate to constrain the second longitudinal side, thefirst slot and the second slot being actuable to respectivelyselectively constrain the first and second longitudinal sides to writeinformation on the display of the substrate.
 15. The device of claim 13,wherein the at least one motorized roller is located between the firstconstraining element and the second constraining element.
 16. The deviceof claim 13, comprising: an imager positioned, in an area adjacent aface of the substrate at which the display is exposed for the imager tooperate the display, including writing information, while the first andthe second longitudinal sides are constrained by the respective firstand second constraining elements.
 17. The device of claim 16, whereinthe display includes electronic paper and the imager includes a writingdevice to operate the electronic paper, including writing information,passing in relation to the writing device.
 18. A device comprising: aconstraining structure to selectively constrain a first longitudinalside of a substrate and an opposite second longitudinal side of thesubstrate; a pair of spaced apart rails between which the constrainingstructure extends and is supported, and relative to which theconstraining structure may move; and an imager to write information on apassive e-paper display of the substrate upon positioning of thesubstrate, via translation of the constraining structure into positionrelative to the imager.
 19. The device of claim 18, wherein theconstraining structure comprises a slot including: a first slot portionto slidably receive the first longitudinal side of the substrate; anopposite second slot portion to slidably receive the second longitudinalside of the substrate; and a third slot portion extending between therespective first and second slots, the third slot portion to receive andto selectively constrain a first end of the substrate, which extendsbetween the respective first and second longitudinal sides of thesubstrate.
 20. The device of claim 19, wherein the constrainingstructure comprises an actuation element to further releasably constrainat least one respective longitudinal side of the substrate within atleast one of the respective first and second slot portions.